This
is just amazing! It's a forward-looking sonar with the additional capability
of identifying likely metallic wrecks using some kind of fuzzy logic database
to pick up on key characteristics of the return signal.

Dexteritas
in Singapore kindly cut us a special deal for a wreckfinder and two sonar
heads that we can switch for either forward or side-looking inputs. We
have the sonar heads mounted either side of the center line near the bow.
They can each be directed forward or sideways by turning them from inside
the boat.

Echopilot is one of only two companies that produce forward-looking sonars
for recreational boats. They come from a military background (naval sonars),
downsizing and reducing the cost of the techology to apply it to the larger,
but much lower-cost, domestic market. The result is extremely good for
the price. I am in the business of researching new sonars myself, and
once considered developing a recreational multi-beam sonar. I concluded
that it wouldn't be possible to bring the price down far enough to be
attractive. These guys have proved me wrong.

Here's
a screen shot of the Wreckfinder on 2-D forward-looking mode while
anchored in 10m of water. The red lettering is mine.

The
bottom is clear to see out to 30m range - great for creeping up
on reef edges.

The
anchor chain shows up well, as does its reflection in the bottom.
The nearly-empty bar on the left-hand side is the probability of
there being a wreck in view - only a few percent in this case, i.e.
not!

The
wreckfinder paints a 2-D screen of what lies ahead of and below the boat,
or a 3-D screen in time-history mode. The latter is useful for sideways-looking
orientations where the boat's forward speed provides the third dimension.
In this mode, the sonar acts like a sidescan, at a fraction of the cost.

So
far our best use has been in feeling our way across uncharted shallows,
where the forward-looking capability gives us warning of what lies ahead.
The wreckfinder typically sees 3-5 water depths ahead, so in 10m of water
you might typically get 40m of warning of a coral reef or rock.

We
also have traditional depthsounders, looking only with a single beam downward
(so you see what you hit, but not before you hit it!) as backup. we have
a depthsounder on our Humminbird NS25 GPS (depth of 8.8m given on lower
left-hand of display) and a simple, but effective, Humminbird 100SX (showing
37 m in a different location) as a last resort.